1. Field of the Invention
The present invention relates to a marine vessel propulsion unit.
2. Description of the Related Art
A prior art marine vessel propulsion unit is disclosed in Japanese Published Unexamined Patent Application No. Sho 55-19681. The marine vessel propulsion unit according to this prior art is an outboard motor. The outboard motor includes an engine, a drive shaft, a propeller shaft, a propeller, a planetary gear mechanism, and a brake lever. The planetary gear mechanism includes a ring gear fixed by operation of the brake lever, a sun gear into which rotation from the drive shaft is input, a carrier from which the rotation input into the sun gear is output, and a plurality of planetary gears arranged between the ring gear and the sun gear.
The outboard motor is arranged such that a driving force of the engine is transmitted from the drive shaft to the propeller shaft via the planetary gear mechanism by operation of the brake lever in a state where a shift position is at a neutral position. Also, the outboard motor is arranged such that the driving force of the engine is transmitted from the drive shaft to the propeller shaft without transmission via the planetary gear mechanism when the shift position is at a forward drive position or a reverse drive position. The planetary gear mechanism is used when the outboard motor drives a hull forward at a low speed, for example, to perform trawling. On the other hand, when the outboard motor drives the hull forward or in reverse at an ordinary speed (when ordinary running of the hull is performed), the planetary gear mechanism is not used.